Fire Fang
by Kayleen756894
Summary: Cinder's been dating Yang and Ruby for years, Ruby always being the one to supply her with blood. Thanks to an incident in Yang's childhood, the blonde has never let Cinder feed from her. Until tonight. Vampire!Cinder AU. Yang x Cinder x Ruby, but focuses on Fireproof.
**A/N: Hi everyone! Well this idea completely spawned out of nowhere. I'm absolutely weak for the idea of Cinder being a vampire and I wanted to attempt a fic exploring a potential relationship between Yang and Cinder (Fireproof) since they're my favourite characters in RWBY. So in this fic Cinder is dating both Yang and Ruby, but her relationship with Yang is what's focused on most. I put the rating as M to be safe because things closer to the end of the fic started getting a little steamier than I expected them to. As if I wrote almost this whole thing in class.**

 **Anyways.**

 **Disclaimer: I own nothing of RWBY! This fic was written for fun and is for entertainment purposes only!**

 **Enjoy everyone, I hope it's an interesting read for you :)**

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 **Fire Fang**

Cinder sighed as she roused from her slumber, instantly recognizing that her arms were significantly emptier than when she had fallen asleep. Her right arm still held a lightly snoring Ruby snugly against her side, but her left arm which had previously rested on Yang's hip now reached at nothing but air in their shared bedroom darkened by the drawn, black curtains, the blonde nowhere in sight.

Ruby snuggled closer and red painted lips stretched outwards, revealing the tip of a fang as Cinder smiled. The ashen haired woman flipped away the blankets and gently maneuvered out of Ruby's arms, the early morning air in their bedroom crisp against Cinder's half naked body, but her pale skin was much colder. Black nails tugged a rebellious bra strap back up her shoulder, reminding Cinder of why she preferred to sleep naked—Yang did, too—but such things made Ruby uncomfortable, so Cinder was more than willing to wear underwear to bed to keep her Little Jewel relaxed when sleeping next to her.

It was the least the centuries old vampire could do when her precious jewel offered her neck whenever Cinder was hungry.

Cinder's amber eyes glowed like molten lava, two shining beacons in the darkness, at the recent memory of the crimson elixir from Ruby's neck gushing down her throat and spilling down her chin, the brunette's tiny moans and the arch of her body into Cinder's suddenly had the vampire craving more in present time. Obsidian claws gently traced the bandage concealing the twin holes in Ruby's neck that would be healed within the day. Then she lifted her hand to Ruby's cheek and caressed the skin beneath with her thumb, her cold touch making Ruby shiver in her sleep and then smile blissfully, the sight making Cinder feel like her heart skipped a beat even though the organ stopped functioning centuries ago.

She loved Ruby. Her jewel was gentle and pure, so pure that Cinder often wondered why Ruby stayed with her. Especially when getting her blood sucked at least weekly made her body weak sometimes, but Ruby insisted that Cinder feed from no one but her. Part of that was due to a sense of justice; Ruby wanted to make sure Cinder was satisfied so she wouldn't hurt anyone else, or decompose into the monster she was before she met Ruby and Yang.

The other part—something sweet, innocent Ruby couldn't even dream to convincingly lie about—was how intimate she found their feeding sessions. Bodies pressed tightly together, fingers tangled in Cinder's ashen mane and leaving scratches down her back, fangs in Ruby's neck and her name tumbling breathily from her young partner's lips; this was all an experience only they shared. An experience only they knew.

Because, even after dating for three years, Yang had never let Cinder feed from her.

Cinder didn't blame the blonde for that. Of course Cinder had fantasized about it—if Yang's blood tasted even half as euphoric on her tongue as her other fluids, Cinder knew the substance would become her personal heroin—but she had never pressured Yang into it and she never would. Not after what happened in Yang's past.

Besides, as long as Cinder had someone to drink from, she wouldn't lose her sanity. Which made Ruby's closeness and trust a blessing that the ashen haired woman would never abandon.

After tucking Ruby back into bed and pressing a soft kiss to her forehead, Cinder draped her black, semi-transparent nightgown over her shoulders and strolled out of their bedroom to search for Yang. Didn't take long to find her out on their apartment balcony, slouched in a chair and taking a drag on a cigarette under the moonlight's watch.

Cinder slid the patio door open and closed quietly to avoid startling the blonde before crossing her arms under her bust and leaning against the wooden balcony railing. "Why aren't you in bed, Little Dragon?" Cinder asked softly, her voice subtle and sweet like the first suckle of a sour candy before the tanginess spiked on your tongue.

Yang glanced up at her, lilac eyes trailing up and down shapely hips and long legs, before she looked away again and shrugged, blowing smoke out of her mouth. "Couldn't sleep," came the soft reply.

Cinder smirked. "You seemed pretty tired earlier once I was through with you." The vampire was pleased at the blush that rose to Yang's cheeks. No doubt Yang remembered every moment, and even if she didn't, the hickeys and scratch marks were still all over Yang's muscular physique to prove it. Amber eyes admired a purplish mark she gifted to Yang's shoulder that was visible thanks to her getup of an orange tank top and black boy shorts, her chosen undergarments whenever Ruby shared the bed with them.

Once Cinder's gaze returned to Yang's, however, she caught the anxious gleam in those lilac depths that Yang attempted to hide. But Cinder was perceptive, and it would take a lot more effort than that to conceal something so important from someone of Cinder's age and experience. "What's wrong, Yang?"

The blonde took another puff from her cigarette. "It's nothing."

"You're lying."

"I don't want to talk about it."

"Okay."

Cinder had lived through centuries of infuriating lovers, through waiting for vampire hunters to make the first move so she could finally strike, and through continuous political and military debates that still, centuries later, were not concluded, all of which tested her patience to the very edge.

She would _not_ lose this patience game.

Soon enough, Yang's leg started to anxiously bob up and down, a motor action beyond her control. Cinder raised a delicate eyebrow at her but didn't say anything. She didn't need to, though, because afterwards Yang sighed and snuffed out her cigarette in the ashtray on the table beside her.

"It's stupid," the blonde murmured, rubbing the back of her neck.

"Nonsense. Of course it isn't."

"You're gonna laugh at me."

Cinder's eyes widened momentarily, the scared woman in front of her reminding her of the Yang she had met years ago. Over the years Yang's body had developed in ways that could infatuate anyone of any gender, her thick mane now brushing her waist and her muscle definition even greater than that of Cinder's, but only now did the vampire realize that the look of fear in Yang's eyes hadn't changed much since they first met.

A part of Yang was still scared of Cinder. Of what she was. Yang would probably never say that out loud, but it didn't take a genius to decipher that clue. But it did make things complicated because despite that fear, Cinder had no doubt that Yang loved her unconditionally.

And right now, that mixture of fear and love was causing some sort of conflict in her poor dragon's brain.

"I won't laugh at you, I promise," Cinder reassured softly, kneeling down in front of Yang to gaze up at the blonde's face, eyes running over every contour of her face and every shift in her expression. "Please tell me what's wrong, Little Dragon. I want to help you, if you'll let me."

Yang let out a deep breath, the last remnants of smoke leaving her system and swishing over Cinder's head in the wind. She bit her lip and for awhile she looked anywhere but at Cinder, trying to stall for time. Cinder let her, because she knew whatever her girlfriend was about to tell her couldn't be rushed. Eventually, lilac orbs met amber.

"When you... um..." Yang stumbled. The blonde's cheeks burned and she rubbed her hair out of her face, probably in an attempt to distract herself. "When you feed from Ruby... what does it feel like?"

Cinder's eyes widened, not expecting the question at all. Not many people other than Ruby herself had ever asked her, despite the hundreds she'd bedded and thousands she'd fed from. No one ever cared enough to ask, and Cinder herself never cared enough to explain.

But this was different. This was special.

"To clarify," Cinder began gently, "are you asking how _I_ feel when I feed from Ruby? Or how _she_ feels when I feed from her?"

"Both, I guess," Yang replied with a nervous shrug. "I'm just curious. You... do know how Ruby feels about it, right? She's mentioned a few things to me, but... I don't know, I guess I want to hear it from you."

Cinder nodded, beginning to understand her dragon's feelings. "My jewel is very vocal," Cinder said, referring to Ruby. "She loves hearing that she made me happy and I always make sure she lets me know her health and comfort level before I feed. If I bite too hard, she'll tell me. If I drink for too long, she'll tell me. I always try and be as gentle with Ruby as possible because... well, the experience is like intercourse for her."

That definitely caught Yang's attention. "What?" the blonde asked quickly.

A small smile stretched Cinder's lips. "You are well aware of Ruby's disinterest and discomfort with sex and the naked form in general, otherwise both of us would have slept unclothed tonight. Despite that, though, I know she's a bit jealous of the time you and I spend together in that regard. She knows she can't have that with me, but the time we spend feeding for her is just as intimate as when you and I have sex. She and I get to be close and we trust each other undoubtedly. It's the same as both of us, no?"

"But... doesn't it hurt her?" Yang argued, sounding more confused than anything.

Cinder chuckled. "I'm biting her, Yang. Of course it's going to hurt, at least a little bit. It's a pain you get used to, but it never fully goes away."

Yang shook her head, brow furrowed. "How could anyone ever enjoy that...?" she murmured quietly.

Cinder's eyes immediately fell to the blistered scar on Yang's neck, left by a beastly vampire—no, a monster, such a thing did not deserve to be called the same species as her—that tore her neck to shreds when she was a child. It was no surprise that the experience left Yang terrified and distrustful of vampires in general, more so than the average person. How Yang ever grew to love Cinder so much that she felt comfortable sleeping next to her every night was a mystery even to the ashen haired vampire.

"Listen to me, Little Dragon," Cinder soothed, grasping one of Yang's hands in hers and gently playing with her fingers, "the process in which vampires feed from their lovers and monsters feed from their prey is completely different."

"How is it different?" Yang asked, a slight bitterness to her tone but Cinder knew it wasn't directed at her. "Sucking their blood is still the whole point, right?"

"Hmm," Cinder hummed, tilting her head and letting her hair cascade over one eye as she considered the question. "Well, yes, there wouldn't be much point of the endeavour if we did not suck blood. It's necessary to our sanity and our survival, after all. However, monsters feed with the intention to kill, but when I do it with my lovers," golden eyes gazed up at Yang through thick eyelashes, making Yang's breath halt, "I aim to make them feel good."

"O-Oh?" Yang stuttered, turning bright red, not able to look away from Cinder's gaze. "And how does that work?"

Cinder grinned mischievously, fangs on full display as she gestured to the hickeys all along Yang's chest and shoulders. "Almost anything can feel good in the throes of passion," she remarked, making Yang's blush reach the tips of her ears. "This just... takes it a step further. It is the ultimate display of trust, and because it is so important and so vulnerable it makes the experience all the more intimate."

"So... so it feels that way for you, too?" Yang asked quietly, the sound so quaint coming from Yang's mouth, whose voice was normally so brash and confident. "It feels intimate?"

" _Absolutely_ ," Cinder replied breathily without missing a beat, hunger spiking in her body after sensing how much quicker Yang's blood was now flowing in her veins. "I never feel closer to Ruby than when I'm feeding from her. Not only do the feeding sessions leave me feeling energized, but they make me feel like... I'm not a monster anymore." Cinder paused for a second when she realized how vulnerable she just sounded, then ignored it and continued. She didn't have time to recollect on her past mistakes. "Because even though I have to hurt Ruby a little to feed from her, the pleasure I give to her is so much more. Not necessarily in a sexual manner, but in a loving one."

Lilac orbs stared at her and flickered back and forth between Cinder's eyes, as if trying to search for any signs of deception. And although Cinder prided herself as a master manipulator, deceiving Yang or Ruby was never her intention. It took a long time for her girlfriends to grow to trust her, to believe that she wasn't like the vampires they knew in the past, and she wasn't planning on betraying their trust.

Eventually Yang nodded, the blush on her face still strong as she looked away. Tan fingers gently held onto the pale ones toying with them, a thumb brushing along the back of Cinder's knuckles, the difference of their skin tones on par with the difference in their body temperatures. Cinder gazed up at the woman caressing her hand, admiring the little show of affection, especially considering how shy Yang looked.

"Why are you so curious about this anyway, Little Dragon?" Cinder asked slowly, a small smile on her features. "You never showed an interest before."

"W-Well, I..." Yang gulped, looking unsure. Cinder squeezed her hand, trying to reassure the blonde that everything would be alright. "You... you said that Ruby was kinda jealous of our fun time, right?" Cinder nodded. "What if I said... that I was kinda jealous of the time you two share, too?"

The vampire's eyes widened, feeling her fangs grow slightly in her mouth as that statement spiked a raw hunger in her core. She never expected Yang to admit something like that, and Cinder would be lying if she said she wasn't filled with anticipation at where this conversation might lead.

"I'm afraid I have to ask you to explain yourself a bit further, Little Dragon," Cinder said, keeping her mouth movements minimal to avoid frightening Yang with her elongating canines. "Are you simply saying you're jealous that your little sister can pleasure me in a way that you can't? Or are you saying," Cinder's eyes darkened, "that you wish to experience it yourself?"

There was a jolt in Yang's breathing and Cinder felt herself growing hungrier by the minute; if she hadn't fed deeply from Ruby last night, and if she were still a fledgling, Cinder would've had trouble controlling herself right then.

"I... want to make you happy."

That sentence sobered Cinder's senses, her fangs shortening back to normal once she realized what this was truly about.

"Pet, do you think that just because you don't let me feed from you that you don't make me happy?" Yang turned away, looking embarrassed and ashamed, but Cinder was quick to make a noise of disapproval and use her free hand to cup Yang's cheek and turn her head back to face her. "Yang, you have no idea how happy you make me. I know how much vampires terrify you, and I completely understand why, so I feel blessed that you want to be with me despite that. You're the bravest human I know, Little Dragon."

"But this isn't something I should have to be brave about," Yang said with a sigh. She held Cinder's palm firmer against her cheek, her skin burning under Cinder's flesh. "I love you so much, Cinder, more than I've ever loved anyone else. I don't want to be scared of you anymore. It's not fair to you."

"I would much rather you be honest about your fears than pretend they don't exist," Cinder argued gently, eyes once again travelling the jagged scar across Yang's neck. "Your fears are justified. I don't blame you."

"But I don't want to be scared of you!" Yang repeated, louder than the first time. "I know you would never hurt me, I know that so well, and yet I still..." The blonde shook her head, looking frustrated with herself. "I need this. I think this is the only way to get the little voice in my head to shut the fuck up."

Cinder was silent for a long time, eyes scanning Yang's flushed, anxious expression and listening to the echoing thump of her rapid heartbeat. She understood where Yang was coming from. Yang always hated looking weak, and even though there was nothing weak about being afraid of something, especially something threatening, Yang never saw it that way. The blonde saw that as a personal failure, and Cinder knew this particular sense of failure had haunted Yang since the two of them had first met, multiplying further once they started dating. And now it truly did seem that Yang wanted to overcome her fears that stemmed from her childhood, whether for personal growth or to increase their level of closeness, but Cinder still had to be sure that Yang was ready for this.

"Okay," Cinder relented with a small breath, making lilac eyes widen slightly. "Okay. I will feed from you. But we will be taking baby steps with this. I'm not going anywhere near your neck today. I'll feed from your hand instead, and make it a smaller bite than I would normally give. I'll have a taste and nothing more." Yang nodded, breath shaky, agreeing. Cinder squeezed her hand, her next words soft but firm, "But if you truly do want this, I need to hear you say it."

"Huh?"

Cinder elegantly rose to her feet, making sure Yang's attention was fully on her body before she slid onto Yang's lap, legs on either side of the chair and her chest flush against Yang's, trapping her dragon against the chair. Yang gulped, eyes frantically shifting between Cinder's, breasts full against the vampire's as she took heavy breaths. The blonde hesitantly placed her hands on Cinder's waist, fingers trembling, while Cinder gripped Yang's shoulders, black tipped claws idly playing with the straps of her partner's tank top.

"If you're sure about this," Cinder began huskily, eyes lidded as she leaned in so close she could feel Yang's breath on her lips, "I need you to tell me _exactly_ what you want me to do to you."

Yang hesitated for a long time, for so long that Cinder thought she was going to change her mind, but ultimately Yang gave her an answer.

"I... want to know what your bite feels like," Yang admitted shyly, shifting under Cinder's weight to get comfortable and potentially shake off some nerves. Then she met Cinder's gaze again. "I want you to bite my hand and drink my blood. Just," Yang licked her lips nervously, her blush brightening, "be gentle, okay?"

Cinder nodded, kissing Yang briefly, and when she pulled back her eyes glowed brighter than the full moon still high in the sky, and she immediately felt Yang tremble beneath her. She trailed her cold hands up and down Yang's arms, fingertips leaving little white lines over rippling muscles and Cinder admired the gooseflesh that followed each stroke of her digits. She gave the same treatment to Yang's legs, journeying across her thighs, past her knees, down her calves and back up again, tracing the blood pumping furiously in Yang's veins.

Then Cinder slowly rolled her hips against Yang's, holding the blonde's hands in place on her waist so she could feel every movement of her body. She cherished how heavy Yang's breathing had become; how her lilac orbs practically faded to red with passionate lust. Cinder smirked when she felt Yang finally respond to her advances, hips gently thrusting against Cinder's in time with her actions. Her hypersensitive sense of smell could already pick up on Yang's arousal and the ashen haired vampire decided to tease her partner just a little bit for it, rolling her hips with a bit more force and lowering her head to subtly brush her nose and lips over Yang's nipples that were peaking through her shirt. Yang groaned, her breasts as responsive as ever, but Cinder pulled away as soon as she heard the noise, feeling a tinge of sadistic pleasure at the disappointment in Yang's eyes.

The vampire slowed her hips, not stopping the movement entirely but making it more sensual. She gently took hold of one of Yang's hands and moved it away from her hip and instead lifted it up to her face. Cinder ran her fingers all along Yang's hand and wrist, squeezing her fingers and lightly tracing her veins. She placed soft, hot kisses all over every sweet inch of skin, and Cinder made sure her gaze was locked onto Yang's before she took Yang's pointer finger into her mouth up to the knuckle and suckled the digit, swirling her tongue around it and gently grazing the skin with her fangs that once again began to elongate. Yang bit her lip to contain an obvious gasp, her blush so fierce it began to travel down her neck, her scent becoming so strong that Cinder was tempted to take her right there on the balcony in the dead of night.

But no. That's not what this was about.

Cinder released Yang's finger with a wet _pop_ , the saliva coated digit glistening under the glow of Cinder's magma-like orbs, shining like gemstones that echoed with enchanted power. With one hand on Yang's elbow to hold her still and the other positioning her hand in front of her face, Cinder parted her lips to put her fangs on full display for Yang, her canines long, white and gleaming; a warning of what was to come. Cinder waited patiently for Yang's nod of approval, then waited a moment later just in case, before she dove into her snack.

Very gently she brought the callused palm to her lips, kissing and licking and preparing before she found the spot she wanted and sunk her fangs only about half a centimetre in, just enough to draw a few drops of blood. Cinder noticed Yang wince, but that was the last thing Cinder saw before she felt her eyes roll back in her head and her whole body vibrate from pure bliss.

Yang's blood was delicious; a few drops were enough for her to know that, even though she had no doubt this treat would be anything but. While Ruby's blood was as sweet as sugar, Yang's had a tangier aftertaste, savoury on her tongue and leaving a pleasant burn as it gushed down her throat. Cinder found the resolve to open her eyes when she heard Yang pant and the vampire purposely grinded against Yang's pelvis as she drank just to hear that alluring reaction again. Yang moaned low in her throat and her entire body trembled under Cinder's poisonous touch; dangerous, yet hot and addictive.

Cinder grinned against Yang's palm and mustered all her willpower to pull away from her treat, licking away the remnants of blood from the wound and using her saliva to hasten the healing process. She licked her lips afterwards, relishing the taste and allowing her fangs to return to normal size and rest comfortably along her jaw. She gently massaged Yang's arm that she had forced to remain still, watching intently as Yang's chest rose and fell as her lover tried to regain control of her breathing.

Cinder cupped Yang's face and leaned in close, resting their foreheads together and using the coolness of her skin to help relax her flustered girlfriend. "Well?" Cinder asked, tone sly and sultry and her tongue nearly poking Yang's lips as she spoke. Quieting down even further she whispered, "Was that intimate enough for you?"

"... I thought," Yang began as she released once last deep breath, "I thought you said this experience wasn't a sexual thing."

Cinder made a low _tsk_ with her lips, a crooked grin on her face. "I said it didn't necessarily _have_ to be sexual. But I thought it was a touch you would... _appreciate_." Yang flushed at her words, pouting slightly, and then Cinder's expression softened. "Are you okay?"

"Yeah," Yang answered with a tired sigh. "That was intense. Is it always like that?"

Cinder nodded and hummed in agreement. "Feeding from someone's neck is much more intimate, though. This was just a little taste, my pet."

"S-Speaking of that," Yang began shyly, wanting to look away but her face was still held firmly in Cinder's pale hands. "Did I... taste okay? Was it good for you?"

Cinder's eyebrows shot up at Yang's insecurity. "You were delectable, Little Dragon, don't even worry about that." Golden eyes suddenly twinkled with amusement. "Do you remember that cheeseburger you had last week that you loved so much you wouldn't let Ruby or I try a bite?"

"Yeah, what of it?" Then Yang's expression fell. "Please don't tell me I taste like a cheeseburger."

Cinder giggled, covering her mouth with the back of her hand. "Of course not. What I was getting at with that was... I find your blood so _delicious_ ," she teasingly dragged her nails down Yang's cheek, "that I would never let any other vampire near you. You're all _mine_."

Cinder chuckled again at the mixture of fear and yearning that crossed Yang's expression before kissing the plump lips in front of her, slowly and sensually. She felt Yang's arms wrap around her bare waist and Cinder smiled, pushing closer against the blonde. They kissed softly for several minutes before Cinder playfully nibbled on Yang's lower lip and then pulled away, putting a small amount of space between their bodies.

"Thank you," Cinder eventually said.

Yang tilted her head. "For what?"

"For wanting to try this with me." Golden eyes momentarily travelled Yang's scar once again. "I know it must have been really frightening to offer."

Yang nodded. "You've proven to me again that you're not like the others." She pulled Cinder in for a briefer kiss, one containing all the love the blonde had for her and, once again, Cinder felt like her dead heart may flare back to life any moment. Yang pulled back and said, "Sorry for being afraid of you all this time."

Cinder shook her head. "No offense taken, Little Dragon. Most people in this world are afraid of me, and honestly I kind of like it. But you and Ruby are safe with me, I promise. Now," Yang yelped as Cinder suddenly stood and lifted her up with her supernatural strength, forcing Yang to wrap her arms and legs around Cinder's lithe, half-naked body to regain any sense of balance, "let's get a bandage on that hand of yours and go back to bed, okay? I'm sure Ruby's lonely without us."

Yang giggled and nodded, snuggling closer to Cinder as the ashen haired woman carried her back inside and locked the door behind her. Eventually Cinder sat her down on the porcelain bathroom countertop, the texture chilly against Yang's bare thighs. Cinder knelt down to grab a bandage from the cabinet below the sink, doing her best to ignore the intensity of Yang's lingering scent in front of her nose as she gently pressed the bandage against Yang's palm.

" _Cinder_."

The way her name was just sighed sent glistening heat and hunger straight to the vampire's core. When she looked up Yang's eyes were lidded with lust and tan arms were already peeling away her tank top.

"I'm glad what I did was able to satisfy you," Yang murmured with a seductive smile, throwing her orange garment across the room and spreading her legs. "But there's no way I'll be able to sleep until you stop being a fucking tease and finally satisfy _me_."

Cinder laughed softly. "Of course," the vampire agreed, eyes bright like fire as she leaned forward and nibbled on Yang's inner thigh with her fangs, "whatever my Little Dragon commands."

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 **A/N: Thanks for giving this pairing and my story a chance. I know I have this listed as complete, but if people want me to add on to this I gladly will. Please review guys, I'd love to know your thoughts! Have a good one :)**


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